Mayweather is 49-0, and looking to finish his career with a perfect 50-0 record. McGregor, the top athlete in his sport, will be taking a break in his prime from UFC to enter the boxing ring against Mayweather. Not since Muhammad Ali took on Japanese professional wrestler Antonio Inoki in 1976 in Tokyo has there been such a spectacle around a matchup in the ring.

McGregor, who has never had a professional boxing match in his career, will now face off against one of the most accomplished boxers in history. And no matter the outcome, the fight and the hype around it should make for one of the best sporting events of the decade.

Here’s everything you need to know about the highly anticipated fight.